The invention concerns a protective suit for use for an operator in a cooling chamber (cold room), in particular in a cooling system for cryopreservation of biological samples. The invention also concerns a glove for use with the protective suit or in a cooling system for cryopreservation of biological samples. Applications of the invention are given in operation of cooling systems for a long-term storage of samples in the cooled state, in particular for cryopreservation of biological samples.
It is known to store biological samples for the purpose of preservation in the frozen state in a cooling system, e.g. in a cryobank (cryopreservation). Cryobanks are typically operated at temperatures below −80° C., in particular at a temperature below the recrystallization temperature of water ice (−138° C.). They contain a cooling agent reservoir with liquid nitrogen (temperature: about −195° C.) and a plurality of individual tanks (so-called cryotanks, mostly Dewar flasks made of double-walled steel). The cryotanks stand in rooms at normal temperature (room temperature) in which operators may stay without particular protective measures. Conventional cryobanks with individual cryotanks have disadvantages when large sample quantities, such as ten thousand up to a million or more samples are to be cryopreserved. Limitations occur as to the effectiveness of the cryotank operation, for the provision of constant cooling conditions and for the automation when operating the cryobank, in particular the sample handling. To overcome these limitations, there is the interest to replace the conventional cryotanks with larger storage units.
An extended cooling system, which is suitable for the cryopreservation of biological samples is described by the inventors of the present invention in a further patent application (not yet published at the priority date of the present invention). The cooling system comprises a cooling chamber and a cooling device, which are provided for cooling of the cooling chamber with liquid nitrogen. Although the cooling system runs fully automatically or semi-automatically in the normal operation mode, i.e. nobody is required to inspect it, operators must be able to inspect it in the cases of maintenance and damage. Without protective measures, humans can, however, not enter rooms with temperatures below −70° C., since frostbites of the skin, the eyes and the lung would be unavoidable and would lead to life-threatening conditions even after a short period of time. For example, it is known that, at the cold poles of the Earth, at temperatures below −60° C., physical activities of the human being with strong inhalation lead to frostbites at the pulmonary alveoli.
Protective measures for human beings in a life-hostile environment are generally known, such as space suits for use in the universe or diving suits. Space suits are, however, not suitable for cooling systems. Space suits require cooling of the astronaut, since overheating of the suit is probable in the free space due to the missing convection. U.S. Pat. No. 3,730,178 A describes a diving suit, which is equipped with a heater. This diving suit is, however, due to its poor thermal insulation capacity and a missing low-temperature resistance of the materials used, not suitable for use in a cooling system.
DE 20 2004 008 966 U1, U.S. Pat. No. 3,182,653 A and US 2006/0144557 A1 describe electric heatable garments, e.g. in the form of an overall, the application of which, however, is restricted to keeping warm the wearer during outdoor activities, such as when hunting, camping or staying in polar regions. These garments are not suitable for protection at temperatures below the low temperatures that occur in nature (approximately −50° C.).
The objective of the invention is to provide an improved protection of an operator in a cooling system for cryopreservation of biological samples, wherein disadvantages and limitations of conventional protective measures are overcome.
This objective is achieved by a protective suit having the features of the invention.